Evaluation of MGIT 960 and the colorimetric-based method for tuberculosis drug susceptibility testing

SETTING: Dr Cetrángolo Hospital, Buenos Aires Province, Argentina. OBJECTIVE: Evaluation of the BACTEC? Mycobacteria Growth Indicator Tube (MGIT)? 960 system and the colorimetric-based method (CMM) for fi rst- and second line drug susceptibility testing (FL-DST, SL-DST) against Mycobacterium tuberculosis. DESIGN: FL-DST was studied using SIRE MGIT 960. Minimal inhibitory concentrations (MICs) for isoniazid (INH), streptomycin, rifampicin (RMP), ethambutol (EMB) and levofl oxacin (LVX) were also determined by CMM using 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT). MICs for amikacin (AMK), kanamycin (KM), capreomycin (CPM), ethionamide (ETH), cycloserine, ofl oxacin (OFX), linezolide (LZ) and moxifl oxacin (MFX) were determined on 94 multidrug resistant M. tuberculosis isolates by MGIT 960 and CMM. Statistical methods were applied to define drug susceptible and drug-resistant isolates on the basis of the comparison between results obtained by gold standards. RESULTS: A total of 1626 clinical isolates were studied. Critical drug concentrations could be defi ned in less than 10 days for both CMM and MGIT 960. CMM was cheaper but more laborious than MGIT 960. The highest performances of both methods were achieved for AMK, RMP, OFX, LZ and MFX, followed by INH, ETH, KM, CPM and LVX (tested only by CMM). CONCLUSIONS: Both methods could be implemented as rapid diagnostic tools to detect drug-resistant isolates in clinical practice.Fil: Morcillo, N.. Provincia de Buenos Aires. Ministerio de Salud. Hospital "Dr. Antonio A. Cetrángolo"; ArgentinaFil: Imperiale, Belén Rocío. Provincia de Buenos Aires. Ministerio de Salud. Hospital "Dr. Antonio A. Cetrángolo"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Di Giulio, B.. Provincia de Buenos Aires. Ministerio de Salud. Hospital "Dr. Antonio A. Cetrángolo"; Argentin

Evaluation of MGIT 960 and the colorimetric-based method for tuberculosis drug susceptibility testing

SETTING: Dr Cetrángolo Hospital, Buenos Aires Province, Argentina. OBJECTIVE: Evaluation of the BACTEC? Mycobacteria Growth Indicator Tube (MGIT)? 960 system and the colorimetric-based method (CMM) for fi rst- and second line drug susceptibility testing (FL-DST, SL-DST) against Mycobacterium tuberculosis. DESIGN: FL-DST was studied using SIRE MGIT 960. Minimal inhibitory concentrations (MICs) for isoniazid (INH), streptomycin, rifampicin (RMP), ethambutol (EMB) and levofl oxacin (LVX) were also determined by CMM using 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT). MICs for amikacin (AMK), kanamycin (KM), capreomycin (CPM), ethionamide (ETH), cycloserine, ofl oxacin (OFX), linezolide (LZ) and moxifl oxacin (MFX) were determined on 94 multidrug resistant M. tuberculosis isolates by MGIT 960 and CMM. Statistical methods were applied to define drug susceptible and drug-resistant isolates on the basis of the comparison between results obtained by gold standards. RESULTS: A total of 1626 clinical isolates were studied. Critical drug concentrations could be defi ned in less than 10 days for both CMM and MGIT 960. CMM was cheaper but more laborious than MGIT 960. The highest performances of both methods were achieved for AMK, RMP, OFX, LZ and MFX, followed by INH, ETH, KM, CPM and LVX (tested only by CMM). CONCLUSIONS: Both methods could be implemented as rapid diagnostic tools to detect drug-resistant isolates in clinical practice.Fil: Morcillo, N.. Provincia de Buenos Aires. Ministerio de Salud. Hospital "Dr. Antonio A. Cetrángolo"; ArgentinaFil: Imperiale, Belén Rocío. Provincia de Buenos Aires. Ministerio de Salud. Hospital "Dr. Antonio A. Cetrángolo"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Di Giulio, B.. Provincia de Buenos Aires. Ministerio de Salud. Hospital "Dr. Antonio A. Cetrángolo"; Argentin

Rapid detection of multidrug-resistant Mycobacterium tuberculosis by multiplex allele-specific polymerase chain reaction

OBJECTIVE: To evaluate a multiplex allele-specifi c polymerase chain reaction (MAS-PCR) to detect multidrugresistant tuberculosis (MDR-TB) clinical isolates and to describe the main mutations conferring resistance to isoniazid (INH) and rifampicin (RMP). DESIGN: Drug-resistant Mycobacterium tuberculosis clinical isolates were tested to detect mutations using MAS-PCR. The genes involved were katG, inhA promoter and rpoB. RESULTS: Among 193 clinical isolates included in the study, 52.6% of the INH-resistant isolates presented a mutation in the katG (315) gene, 28.1% in the inhAP (−15) and 3.0% in both. For the rpoB gene, 60% of the RMP-resistant isolates showed a mutation in codon 531, 17.5% in 526 and 2.5% in 516. Results were compared with those obtained by sequencing, and 100% concordance was obtained for the detection of the mutation in katG (315), 94.1% for inhAP (−15), and 97.8% for rpoB. The global concordance between both methods was 98%. CONCLUSIONS: The MAS-PCR system allowed the simultaneous and rapid detection of approximately 80.0% of the drug-resistant clinical isolates. This method could be used as a rapid and simple screening tool to detect drug-resistant TB in clinical practice.Fil: Imperiale, Belén Rocío. Provincia de Buenos Aires. Ministerio de Salud. Hospital ; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cataldi, Ángel Adrián. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Morcillo, N. S.. Provincia de Buenos Aires. Ministerio de Salud. Hospital ; Argentin

Self-pulsing dynamics of ultrasound in a magnetoacoustic resonator

A theoretical model of parametric magnetostrictive generator of ultrasound is considered, taking into account magnetic and magnetoacoustic nonlinearities. The stability and temporal dynamics of the system is analized with standard techniques revealing that, for a given set of parameters, the model presents a homoclinic or saddle--loop bifurcation, which predicts that the ultrasound is emitted in the form of pulses or spikes with arbitrarily low frequency.Comment: 5 pages, 5 figure

Excitability in a nonlinear magnetoacoustic resonator

We report a nonlinear acoustic system displaying excitability. The considered system is a magnetostrictive material where acoustic waves are parametrically generated. For a set of parameters, the system presents homoclinic and heteroclinic dynamics, whose boundaries define a excitability domain. The excitable behaviour is characterized by analyzing the response of the system to different external stimuli. Single spiking and bursting regimes have been identified.Comment: 4 pages, 5 figure

Chemical and structural changes of calcium ion exchange silica pigment in 0.5M NaCl and 0.5M Na 2SO4 solutions

This paper studies the suitability of an environmentallyfriendly anticorrosive pigment (Si/Ca) to replace Cr(VI) pigments, characterising the initial pigment and the products obtained after interaction with aqueous solutions containing aggressive ions from a corrosion viewpoint (Cl - and SO42- ). X-ray diffraction (XRD), calorimetry (DTATG), Fourier transform IR spectroscopy (FTIR) and scanningelectron microscopy (SEM-EDAX) techniques areused. The ion exchange capacity of the pigment is studied and the solutions obtained after the pigment-solution interaction are analysed. The results obtained show that a series of physical/chemical transformations take place in the pigment on interaction with the Cl - and SO42-  solutions, in some cases accompanied by the appearance of new crystalline phases, mainly calcium and sodium silicates and calcium sulphate. Analysis of the solutions obtained after interaction shows a rise in the calcium content as theionic force of the medium increases. These results suggest that the mechanism by which the pigment acts is not only based on ion exchange reactions but also on a structural modification of the pigment itself and consequently on (co)precipitation reactions that form insoluble compounds in the studied aggressive media

Health-5G: A Mixed Reality-Based System for Remote Medical Assistance in Emergency Situations

Mixed reality is the combination of virtual and augmented reality to interactively and believably merge physical and computer-generated environments. This paper discusses the design of Health5G, a scalable mixed reality-based system that facilitates and supports emergency response by medical emergency teams. Health-5G is supported by a distributed architecture divided into four interrelated applications responsible for advanced computer-human interaction, effective real-time videoconference, medical device integration, and communication infrastructure, respectively. The mixed reality layer is provided by the headset Microsoft Hololens 2™. Health-5G is based on scenarios in which emergency personnel wear mixed reality glasses that can transmit audio, video, and data streams bidirectionally over a 5G network to medical specialists stationed in a hospital at any distance. Thanks to Health-5G, the specialist will be able to access the emergency team’s point of view at any time and provide verbal and visual instructions, including gestures and positioning of graphical markers in 3D space. In this way, emergency personnel can provide the best possible care to the patient without having to wait for them to arrive at the hospital, saving a lot of time in scenarios where every second can make a difference. Health-5G also addresses the integration of medical devices and the collection of the patient’s medical data in a scalable way through optical character recognition. A case study is discussed where Health-5G is used to attend a patient in the street suffering from syncope due to third-degree atrioventricular block. Latency and performance tests over a 5G network are also discussed. To the best of our knowledge, there is no comprehensive solution in the literature that provides all the capabilities offered by Health-5G in terms of functionality and advanced interaction mechanisms within the context of remote, immersive support in emergency situations